Titanic is one of those rare movies that wasn’t just a hit—it was a phenomenon. It won 11 Oscars, including Best Picture, and made mega-stars out of Kate Winslet and Leonardo DiCaprio. But here are a few things you might not know about one of the third highest-grossing film in Hollywood history.

1. Titanic's most iconic line was improvised.

When Leonardo DiCaprio first got up on the end of the ship, he improvised the line “I'm the king of the world!” Cameron liked the line so much that he kept it in the movie. Though the line would go on to be parodied countless times—including at the Oscars—it landed at #100 on the American Film Institute's list of the greatest movie quotes.

2. JACK DIDN'T HAVE TO DIE.

One question that has plagued Cameron for the past 20-plus years is: Did Jack really have to die? In an episode of MythBusters that examined whether both Jack and Rose could have stayed on the wooden beam without it sinking, Cameron himself came on the show to admit that the movie's dramatic ending depended on Jack dying. “If [he] lives, the movie makes a tenth as much,” quipped Cameron.

In November of this year, Cameron was still being grilled about it. Though he repeated that the decision to kill Jack was “an artistic choice,” as the movie “is about death and separation” in an interview with Vanity Fair, he still defended the means, saying he tested the floating board prop itself to gauge its buoyancy.

3. TITANIC WON 11 OSCARS—BUT NONE OF THEM FOR ACTING.

Although 87-year-old Gloria Stuart (Old Rose) was considered a lock for the Best Supporting Actress trophy, she lost to Kim Basinger for L.A. Confidential. Winslet was nominated for Best Actress but lost to Helen Hunt for As Good as It Gets. It would take Winslet another five nominations before she’d take home a statue (for The Reader in 2009).

4. KATE WINSLET LEARNED SHE HAD LANDED THE PART OF ROSE WHILE SHE WAS WEARING A STRAITJACKET.

The day Winslet learned she had landed her star-making role, she was in England filming Hamlet with Kenneth Branagh. After getting off the phone with her agent, she then went to work, which meant wearing a straitjacket to film Ophelia's famous breakdown scene.

5. A NAKED DRAWING OF WINSLET SOLD FOR THOUSANDS.

Paramount Pictures

In 2011, a company called Premiere Props auctioned off one of the movie's most iconic pieces of memorabilia: one of the drawings Jack made of Rose, who is wearing nothing but the Heart of the Ocean necklace. Although the identity of the buyer and the final price were not released publicly, the highest known bid was $16,000. The drawing was done by Cameron, not DiCaprio.

6. THE FREEZING COLD WATER WASN'T COLD AT ALL.

“The water in the tank was about 80 degrees, so it was really like a pool,” James Cameron explained of the filming of the water scenes. “All of the cold, frigid water was added later.”

7. A FAMOUS REAL COUPLE GETS A SMALL CAMEO IN THE MOVIE.

Ida and Isidor Straus, who founded Macy's, were on the Titanic and died together on the ship. They get a brief, unidentified cameo in the film as the elderly couple lying in bed together as the water washes over them. They are named in the film's credits, though: Lew Palter and Elsa Raven portrayed them.

8. AN ALTERNATE ENDING WAS FILMED.

An alternate ending of the movie was filmed in which Bill Paxton’s character finally does get to hold the Heart of the Ocean necklace in his hand, and Stuart’s character gives him a speech about making every day count.

9. NEIL DEGRASSE TYSON MADE AN IMPORTANT CHANGE TO THE MOVIE.

The noted astrophysicist didn’t see Titanic until years after it was released, but he took issue with the scene where Rose is lying on the piece of driftwood and looking up at the sky. He sent James Cameron “quite a snarky email” (Cameron’s description) explaining that the star field Rose saw in the movie isn't the one she would have seen in real life at that place and time. Cameron—ever the perfectionist—re-shot the scene for the 3-D edition of the movie.

10. THE FILM SET A NON-BOX OFFICE RECORD.

Because it remained in cinemas for so long, Titanic was the first movie ever released on VHS while it was still playing in theaters. Its popularity was so massive, with people lining up for repeat viewings, that some theaters reportedly had to get new film reels to replace the ones they’d worn out.